1. Field of the Invention
One disclosed aspect of the embodiments relates to an image pickup apparatus and an image pickup system.
2. Description of the Related Art
An image pickup apparatus including a plurality of photoelectric conversion units arranged in a two-dimensional array is used in, for example, digital cameras and digital camcorders.
A technology for detecting a focus state using a phase difference method has been used in image pickup apparatuses. Japanese Patent Laid-Open No. 2001-250931 describes an image pickup apparatus including two photoelectric conversion units under each of a plurality of microlens in order to receive light rays separated from a light ray collected by the microlens. The photoelectric conversion units are configured so as to receive light rays from different pupil planes of an image-capturing lens.
As illustrated in FIG. 8 of Japanese Patent Laid-Open No. 2001-250931, in the image pickup apparatus, each of two photoelectric conversion units disposed under a microlens has a transistor that reads a signal. More specifically, three transistors B07, B09, and B11 are disposed for a first photoelectric conversion unit PD1. In addition, three transistors B08, B10, and B12 are disposed for a second photoelectric conversion unit PD2. Furthermore, Japanese Patent Laid-Open No. 2001-250931 describes that any light shielding member is not disposed between the photoelectric conversion units disposed under a microlens.
Still furthermore, as the number of pixels of an image pickup apparatus increases in order to capture a high-resolution image, the area or the aperture ratio of the photoelectric conversion unit (e.g., a photodiode) is reduced. To solve such a problem, Japanese Patent Laid-Open No. 10-256521 describes a technology for sharing an electrical component by a plurality of pixels.